Pavement Sweeper with Improved  Filter Screen System

ABSTRACT

An improved filter screen system for a pavement sweeper ( 10 ) includes one or more filter screen assemblies ( 50 ) that are so-mounted as to slide-out from the main body of the debris hopper ( 18 ) for cleaning and, if desired, be separated from the debris hopper ( 18 ) for replacement. The slide-out screen system avoids the need for a worker to crawl into the interior of the debris hopper ( 18 ) to clean the filter screens ( 56 ).

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional patent application 61/438,617 filed Feb. 1, 2011 by the applicants herein and in common assignment herewith, the disclosure of which is incorporated herein by reference.

BACKGROUND

The present invention relates to mechanized sweepers of the recirculating air-flow type used for sweeping paved areas, parking areas, and roads and, more particularly, to such sweepers using one or more screens to filter debris from the air flow, and, still more particularly, to an improved filter screen system for such sweepers.

Various types of mechanized wheeled vehicles are known for use in sweeping paved surfaces. For example, truck-mounted sweepers are known for sweeping highway and roadway surfaces while other types of sweepers are more suited for sweeping parking lots and parking garages. In general, pavement sweepers include a standard truck chassis and a sweeper unit that is mounted to the truck chassis. In most cases, the sweeper unit includes a motor-driven fan, a pick-up head, and a debris-separation hopper. The fan creates a recirculating air flow with the air flow passing from the hopper to and through the pick-up head where dust, particles, debris, etc. is entrained in the air flow with debris-entrained air flow entering into the hopper where dust, particles, debris, etc. are removed from the air flow by known separation techniques including the use of screens to filter or otherwise separate larger particles and debris from the air flow.

Historically, the filter screens are contained within the hopper and can have their filtering efficiency compromised by debris that clogs the openings in the filter screens; this debris including bits of textiles, twigs, leaves, pet hair, plastic materials, string, rope, electrical wire, etc. Typically, the screens are periodically cleaned by a worker who climbs into the hopper with a power washer to spray high-pressure water against the screens to remove some of the debris and who then uses a scrapper or similar tools to physically scrape the remaining material from the screens. In some cases, it is also been found helpful to use a hand-held propane torch to burn or melt difficult-to-remove materials.

SUMMARY

An improved filter screen system for a pavement sweeper includes one or more filter screens that are so-mounted as to slide-out from the main body of the debris hopper for cleaning and, optionally, be removed from the debris hopper for cleaning or replacement. The system avoids the need for a worker to enter into the interior of the hopper to clean the filter screens.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a representative sweeper in accordance with the present invention;

FIG. 2 is a side elevation view of a debris hopper showing a lid displaced upwardly from the body of the hopper;

FIG. 3 is an exploded perspective of the debris hopper showing the lid and two screen assemblies displaced from their installed positions;

FIG. 3A is a detail view of a mechanical stop adjacent two filter screen assemblies;

FIG. 4 is a perspective view of a single filter screen assembly;

FIG. 5 is a front elevation view of the filter screen assembly of FIG. 4;

FIG. 6 is a rear elevation view of the filter screen assembly of FIG. 4; and

FIG. 7 is a side elevation view of the filter screen assembly of FIG. 4 taken from the interior end thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIG. 1, a sweeper vehicle incorporating the present invention is designated by the reference character 10 and includes a commercial truck chassis 12 upon which a sweeper unit 14 is mounted. The truck chassis 12 shown is representative of many vehicles from different manufacturers upon which the sweeper unit 14 can be mounted or otherwise adapted; chassis of this type typically include frame members (unnumbered) upon which the sweeper unit 14 is mounted or otherwise supported. The sweeper vehicle 10 includes a pick-up head 16 that extends laterally substantially across the side-to-side width of the truck chassis 12 from one side to the other. The pick-up head 16 is typically suspended below the truck chassis 12 by links, bars, or chains (not specifically shown), or a combination thereof, so that the pick-up head 16 can ride on or be supported a small distance above the surface to be sweep as the sweeper vehicle 10 moves forward.

A debris-receiving hopper 18 receives dust, debris, particulates, debris, and other air-entrainable materials swept from the pavement surface; as shown, the hopper 18 includes a hatch or lid 18-1 that is pivotally mounted near the forward end of the hopper 18 and raised or lowered about an axis A_(x) by two hydraulic cylinders H1 and H2 for the purpose of emptying the hopper 18 or gaining access to the interior thereof. The pick-up head 16 includes an air-flow outlet (not specifically shown) that connects through a flex-hose 20 to enter the suction inlet or debris-uptake inlet 22 of the debris-receiving hopper 18. Any debris-entrained air flow exits the air-flow outlet of the pick-up head 16 and flows through the flex-hose 20 to enter the suction inlet or debris-uptake inlet 22 of the debris-receiving hopper 18. A motor-driven fan assembly 24 is mounted at the front side of the sweeper unit 14 and is designed to establish a recirculating air flow through the hopper 18 as is conventional in this art.

Additionally, a motor-driven rotatable gutter broom 26 is shown mounted on the driver side of the vehicle to sweep debris into the path of the pick-up head 16. The gutter broom 26 is mounted at the end of pivotable arm 28 that, in turn, is pivotally mounted at or near the distal end of standoff structure 30 connected to the truck frame (unnumbered). While not specifically shown, a similar gutter broom arrangement is often mounted on the opposite side of the vehicle. The use of a standoff structure 30 allows the gutter broom 26 to be “tucked in” behind the standoff structure 30 when the gutter broom 26 is retracted inwardly toward the frame of the truck chassis 12.

In FIG. 1, a tool/accessory box 32 (typically fabricated from a rotomolded plastic) is optionally attached to the rear of the sweeper vehicle 10.

In FIG. 1, various hydraulic hoses, pneumatic lines, and electrical wires are not shown for reasons of clarity.

FIG. 2 is a side view of the hopper 18 showing the lid 18-1 separated from the body of the hopper 18 in order to show a full side view of the lid 18-1; as shown by the bidirectional arrow, the lid 18-1 is rotatable about an axis A_(x) between a closed position (FIG. 1) and a open position under the control of the hydraulic cylinders H1 and H2 shown in FIG. 1. In contrast to prior designs, the lid 18 extends almost the “full length” of the hopper 18 to allow greater access to the interior of the hopper 18.

As is typical in this art, various access doors and ports 34 are provided in the side of the hopper 18. As explained in more detail below, the hopper 18, in the preferred embodiment, is equipped with a slide-out screen assembly 50 on each side of the hopper 18. In FIG. 2, the screen assembly 50 is held in place within the hopper 18 by spring-latches 36 on each end of the screen assembly 50, each latch 36 having a pull-handle 36-1 to release the latch 36.

FIG. 3 is an exploded perspective view of the of the hopper 18 with the lid 18-1 “lifted” from its installed position and showing left-side and right-side screen assemblies 50 retracted from their installed position. The hopper 18 is typically formed as a weldment from pre-cut panels. In the embodiment of FIG. 3, the hopper 18 includes an open framework 40 having longitudinal members 40-1 and lateral members 40-2 designed to support the screen assemblies 50 in their installed configuration. Two spaced-apart mechanical stops 42 are secured to a partition strip 40-3 to contact and guide the inner end of each screen assembly 50 toward and to their respective installed position. As shown, the screen assemblies 50 are in a generally or substantially horizontal plane as the move between the installed and their retracted positions. Respective openings 44 are formed through the sidewalls of the hopper 18 and are shaped to received their respective screen assembly 50 therethrough.

As shown in FIG. 3A, the mechanical stops 42 includes first and second inclined flanges 42-1 and 42-2. As shown by the screen assembly 50 on the right side of FIG. 3A and as indicated by the left-pointing arrow, as the screen assembly 50 is pushed inwardly towards its installed position, a portion of the inner end thereof will engage the underside of the inclined flanges 42-2 of the mechanical stops 42. In the event the inner end of the filter assembly 50 is raised relative to its supporting framework, the inner end will engage the inclined surface and “ride” down that surface so that the inner end of the screen assembly 50 is guided toward its supporting framework and into its installed position. The inner end of the filter screen 50 is thus constrained from any tendency to lift off its underlying support framework 40. The screen assembly 50 shown on the left in FIG. 3A shows a screen assembly 50 in its installed position with the flanges 42-1 limiting any tendency for the inner end thereof to lift upwardly. As shown in FIG. 3, the mounting opening 44 is formed in each side of the hopper 18 and is shaped to accept its respective screen assembly 50.

As shown in the detail views of FIGS. 4-7, the screen assembly 50 include a panel 52 and an attached open framework 54 with various longitudinal members 54-1 and lateral members 54-2 to define various openings therebetween. While not specifically shown in detail, a filter screen or filter mesh 56 is attached to or assembled to the framework 54 to filter debris from the air flow that passes through the screen assembly 50; in the preferred embodiment, a #9 expanded metal (mild steel, corrosion-resistant steel, or a stainless steel) screen is suitable. A stop structure 58, in the form of a vertically aligned plate, is mounted on the inner longitudinal member and functions to prevent the screen assembly 50 from being pulled directly out of this mounting opening 44. The panel 52 is larger in area than that the opening 44 and may include gasketing (not shown) or other sealing arrangements to minimize undesired leakage of debris-entrained air therethrough into the ambient surroundings.

In order to access a screen assembly 50 for inspection or cleaning, the spring latches 36 are released and the screen assembly 50 is pulled laterally outward until the stop structure 58 ‘catches’ an interior surface of the debris hopper 18. In this retracted position, the screen assembly 50 can be power washed and any remaining material removed physically with scraper type tools and, if necessary, a hand-held propane torch can be used to remove additional debris. If desired, the entire screen assembly 50 can be removed by lifting the remote or distal end of the retracted screen assembly 50 until the stop structure 58 ‘clears’ the interior surface of the debris hopper 18 to thus allow the screen assembly 50 to be removed completely for cleaning, inspection, or replacement.

After any cleaning, inspection, or repair is accomplished, the screen assembly 50 can be conveniently re-installed and latched into position for use. The system allows for increased operational efficiency since clogged screen assemblies 50 can be cleaned without the need for a worker to enter into the debris hopper 18 or clogged screen assemblies 50 can be removed from the sweeper and be immediately replaced with a replacement set of clean screen assemblies 50 to provide a very short filter-screen maintenance cycle.

In the illustrated embodiment, the filter screens have been shown as mounted on the lateral sides of the debris collection hopper, as can be appreciated, the invention is not so limited and can include, for example, mounting the filter screens through, for example, openings in the front facing portion of the debris collection hopper.

As will be apparent to those skilled in the art, various changes and modifications may be made to the illustrated embodiment of the present invention without departing from the spirit and scope of the invention as determined in the appended claims and their legal equivalent. 

1. A pavement sweeper of the type having a recirculating air flow system for establishing a recirculating air flow through a pick-up head, a debris hopper for collecting debris, and a fan for establishing a recirculating air flow, comprising: at least one filter screen, the debris hopper having at least one opening through a wall surface thereof for receiving the filter screen, the filter screen mounted for sliding movement through the opening to an installed position for removing debris from the recirculating air flow and for sliding movement through the opening to a retracted position.
 2. The pavement sweeper of claim 1, wherein the filter screen is moved to and from its installed and retracted positions in a substantially horizontal plane.
 3. The pavement sweeper of claim 2, wherein the filter screen, when in its retracted position, is separable from the debris hopper.
 4. The pavement sweeper of claim 3, further comprising means for blocking withdrawal of the filter screen from the opening.
 5. The pavement sweeper of claim 1, further comprising a framework within the debris hopper for supporting the filter screen during movement between its installed position and its retracted position.
 6. The pavement sweeper of claim 5, further comprising a mechanical stop for engaging an inner end of the filter screen to urge the inner end of the filter screen toward a portion of its supporting framework.
 7. The pavement sweeper of claim 6, wherein the mechanical stop comprises an inclined surface for engaging a portion of the inner end of the filter screen to urge the inner end of the filter screen toward a portion of its supporting framework.
 8. A pavement sweeper having ground-engaging wheels and of the type having a recirculating air flow system for establishing a recirculating air flow through a pick-up head, a debris hopper for collecting debris, and a fan for establishing a recirculating air flow, comprising: a first filter screen and a second filter screen, the debris hopper having at least a first opening and a second opening through a respective wall surface thereof for receiving the first filter screen and the second filter screen, respectively, the filter screen mounted for sliding movement through the first opening to an installed position for removing debris from the recirculating air flow and for sliding movement through the first opening to a retracted position and the second filter screen mounted for sliding movement through the second opening to an installed position for removing debris from the recirculating air flow and for sliding movement through the second opening to a retracted position.
 9. The pavement sweeper of claim 8, wherein each filter screen, when in its retracted position, is separable from the debris hopper.
 10. The pavement sweeper of claim 8, wherein the each filter screen is moved in a substantially horizontal plane between its installed position and its retracted position.
 11. The pavement sweeper of claim 8, further comprising means for blocking withdrawal of a filter screen from its respective opening.
 12. The pavement sweeper of claim 8, further comprising a framework within the debris hopper for supporting each filter screen during movement between its installed position and its retracted position.
 13. The pavement sweeper of claim 8, further comprising a mechanical stop for engaging an inner end of each filter screen to urge the inner end of the filter screen toward a portion of its supporting framework.
 14. The pavement sweeper of claim 13, wherein the mechanical stop comprises an inclined surface for engaging a portion of the inner end of the filter screen to urge the inner end of the filter screen toward a portion of its supporting framework. 